Scientists convert CO2 to solid coal

Australian Research Council DECRA Fellow Dr Torben Daeneke and Vice-Chancellor’s Research Fellow Dorna Esrafilzadeh, RMIT University.

Scientistshave used liquid metals to turn carbon dioxide back into solid coal at room temperature, in a breakthrough for carbon capture and storage.

A research team comprising UNSW’s Professor Kourosh Kalantar-zadeh and newly appointed Scientia Fellow Dr Dorna Esrafilzadeh together with their former RMIT colleague Dr Torben Daeneke has demonstrated the new technique.

Published in the journal Nature Communications, the research has been hailed as offering an alternative pathway for the safe and permanent removal of greenhouse gas from the atmosphere.

“The most important thing is we can close the loop for CO2,” Professor Kalantar-zadeh said. “From coal to CO2 and back to coal again, at room temperature and at low consumed energy – this is something we could only dream of doing before, but no-one knew how.”

Dr Daeneke explained how converting CO2 into a solid could be a more sustainable approach than other methods used to date such as capturing it in liquid form.

“While we can’t literally turn back time, turning carbon dioxide back into coal and burying it back in the ground is a bit like rewinding the emissions clock,” Dr Daeneke said.

“To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable.

“By using liquid metals as a catalyst, we’ve shown it’s possible to turn the gas back into solid carbon at room temperature, in a process that’s efficient and scalable.

“While more research needs to be done, it’s a crucial first step to delivering solid storage of carbon.”

The technique sees carbon dioxide dissolved in electrolyte liquid and a small amount of the liquid metal, which is then charged with an electrical current.

The CO2 converts into solid flakes of carbon, which are naturally detached from the electrode and collected.

The process produces synthetic fuel as a by-product.

The research is supported by the Australian Research Council Centre for Future Low-Energy Electronics Technologies (FLEET) and the ARC Centre of Excellence for Electromaterials Science (ACES).

The collaboration involved researchers from Germany (University of Munster) and the US (North Carolina State University) and Australia (UNSW, University of Wollongong, Monash University, QUT).